{4-t-Bu-2,6-[P(O)(O-i-Pr)2]2C6H2Sn}2: an intramolecularly coordinated organotin(I) compound with a Sn-Sn single bond, its disproportionation toward a diorganostannylene and elemental tin, and its oxidation with PhI(OAc)2.

Syntheses of the intramolecularly coordinated organotin(I) compound {4-t-Bu-2,6-[P(O)(O-i-Pr)(2)](2)C(6)H(2)Sn}(2) (2), which crystallized in two different pseudopolymorphs 2 and 2·C(7)H(8), of the diorganostannylene {4-t-Bu-2,6-[P(O)(O-i-Pr)(2)](2)C(6)H(2)}(2)Sn (3) and of the organotin(II) acetate 4-t-Bu-2,6-[P(O)(O-i-Pr)(2)](2)C(6)H(2)SnOAc (4) are reported. The compounds were characterized by multinuclear NMR, IR (3 and 4), UV-vis spectroscopy (2), electrospray ionization mass spectrometry (3 and 4), and single-crystal X-ray diffraction analyses. Density functional theory calculations on compound 2 revealed the stabilizing effect of the intramolecular P═O → Sn coordination.